Elevator rack

ABSTRACT

A rack for horizontally supporting a plurality of trays, baskets, or pans vertically spaced apart from each other and in vertical alignment. The rack includes a foot-operated elevator for simultaneously lifting all the trays supported by the rack form one level to the next higher level. The rack is adapted to receive and to be loaded with trays at a lower level and to deliver trays at an uppermost level.

United States Patent H 13,s91,01s

lnventor Blasie dAnka Cleveland, Ohio Appl. No. 828,666 Filed May 28,1969 Patented July 6, 1971 Assignee Crwcent Metal Products, Inc.

Cleveland, Ohio ELEVATOR RACK 7 Claims, 7 Drawing Figs.

U.S.Cl 211/126, 198/24, 198/219, 312/214, 312/236 Int. Cl A471 3/14,865g 25/08, 865g 47/82 Field ofSearch 211/126, 133, 1.5, 176, 1 E;198/219, 107, 24; 108/44, 59; 312/214, 236

[56] References Cited UNITED STATES PATENTS 270,695 1/1883 Phillips198/219 Primary Examiner-Ramon S. Britts Attorney-Bosworth, Sessions,Herrstrom & Cain ABSTRACT: A rack for horizontally supporting aplurality of trays, baskets, or pans vertically spaced apart from eachother and in vertical alignment. The rack includes a foot-operatedelevator for simultaneously lifting all the trays supported by the rackform one level to the next higher level. The rack is adapted to receiveand to be loaded with trays at a lower level and to deliver trays at anuppermost level.

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flaws-$ {@m ELEVATOR RACK BRIEF SUMMARY OF THE INVENTION This inventionis directed to a rack for holding and supportirig horizontally aplurality of trays, baskets, or pans at vertically spaced-apartindividual tray support levels in a substantially vertically alignedarrangement and for simultaneously lifting or elevating all the trays,baskets, or pans supported from one support level in the rack to thenext by a single motion of a foot'operated treadle. The rack may beenclosed in an insulated cabinet maintained at a preselected conditionof temperature and/or moisture by appropriate apparatus such as aheater, refrigerator, humidifier, or dehumidifier.

Such racks are useful, for example, for receiving and storing preparedfood and maintaining it in a desired condition after it has beenprepared and for successively presenting the food stored at a dispensingstation or level. The food to be stored in the cabinet is placed on orin trays, baskets, and pans. Each tray, for example, is successivelyplaced in the lowermost support position or level of the rack. As eachnew tray is added to the rack, the preceding trays are lifted by therack elevator to the next higher tray-supporting position. The cabinetis arranged so that the tray in the top position is readily accessiblefor presentation and delivery of the food on it.

Such an elevator rack is especially useful when food must becontinuously prepared and available to be served on demand. In this kindof service, the food, as prepared, is loaded into the bottom of therack. The food to be served is taken from the top tray in the rack. Thetrays inbetween hold a reserve supply of prepared food and maintain itat a desired condition. By use of such an elevator rack, the food ispresented for service in the same order in which it was prepared andloaded onto the rack, thus, insuring the orderly and timely serving ofthe food and preventing the retention of prepared food in the rack foran overly long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of apreferred embodiment of this invention showing primarily the exteriorappearance and detail;

FIG. 2 is a perspective view with two walls of the cabinet shown in FIG.1 broken away to reveal the supporting and elevating mechanism andstructural details of the FIG. 1 em- .bodiment;

FIG. 3 is a top plan view of the cabinet and rack shown in FIG. 1;

FIG. 4 is a partial section through the apparatus shown in FIG. 2, takenin the plane of line 44; and

FIGS. 5, 6, and 7 are sequential elevation views of a portion of thesupporting and elevating means of a preferred embodiment andillustrating its operation.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT A rack embodying thisinvention is shown in FIG. 1 as preferably enclosed in a cabinet. Forconvenience in describing the invention, side F will be referred to asthe front of the cabinet and/or rack; the opposite face R will bereferred to as the rear; and the faces therebetween marked S will bereferred to as side faces.

The rack, with cabinet, is provided with insulated sidewalls on each ofthe faces mentioned above and a base 10 supported on legs 11. Ifdesired, legs 11 may be fitted with casters or wheels. A loading door Dis provided in the lower part of front face F and a transparentprotective cover C is hinged along one edge, for example, and covers thetop of the rack and the tray, baskets, or pans therein. The cabinet andrack is loaded through door D and the contents are removed from the rackat the upper or top surface by lifting cover C.

Trays, wire baskets, pans or other similar containers can be used withelevator racks embodying this invention. All such articles will becollectively referred to in the description that follows as trays.Limitation as to size, kind, or type, if any, will become apparent as anunderstanding of the invention is gained. The preferred embodiment shownand described is adapted for use with conventional metal or Fiberglastrays and the particular trays shown form no part of the inventionthemselves.

In FIG. 2, the left side panel S and the front panel F are broken awayto reveal the operational structure for supporting horizontally aplurality of trays at vertically spaced-apart tray support levelsarranged in vertical alignment and for simultaneously elevating orlifting all the trays from their supported positions to the next highersupport level. A conditioning apparatus such a a heater or cooling unit,is shown at 12 and is intended to represent any type of device forheating, cooling, or otherwise conditioning the interior of the cabinetand its contents. This device may be provided, for example, withsuitable manual or automatic controls such as on-off switch 13 and athermostatic control 14 on its front face.

As shown, the top of conditioning apparatus 12 is provided with a flatsurface 15 of substantial area well adapted to receive and support thetray, basket, or pan being loaded into the rack. Obviously, otherappropriate means, such as rails, plates, grids, and the like, may beprovided for this purpose. It will be understood that the use of the topsurface 15 of conditioning apparatus 12 is limited to supporting thetray being loaded into the cabinet and is not necessarily related to itsconditioning function. Whatever means are employed for receiving thetray at the loading level in the cabinet, it is preferred that theentering tray be well supported and guided in and to its proper positionin the rack to make loading as easy an operation as possible and toprevent any inadvertent or accidental tipping. The continuousfront-to-back and sideto-side support provided by the flat surface ofconditioning unit 12, as shown provides the preferred kind and extent ofsupport and guidance for the entering tray.

A vertical post or column 16 is mounted and fixed by an angle bracket 17to each of the four comers of base 10. As seen in the plan view of FIG.3, the four posts stand at the corners of a rectangle. The upper ends ofposts 16 are held in fixed relationship by any suitable means, such asstructural plates and angles 18 and 19. Preferably, base 10 and posts16, interconnected and stiffened by angle brackets 17, plates 18, andangles 19, comprises a substantially rigid interconnectedself-supporting framelike structure which does not depend upon theexterior panels of the cabinet for structural support. Rather, theexterior panels are preferably supported by and attached to thestructural elements of the rack described above. It is convenient andpreferred to have the panels attached to the rack by some meanspermitting them to be easily removed and replaced for ease in cleaningand caring for the apparatus.

Posts 16 on the left side of the rack are laterally spaced from those onthe right side by a distance sufficient to permit the trays intended foruse with the rack to easily fit between them. The two posts 16 at thefront side F of the rack are spaced from the two posts 16 at the back Ra distance substantially less than the corresponding front-to-backdimension of the trays to be used in order that tray supports attachedto the posts can positively engage the trays to be supported at pointsintermediate their ends and without risk of missing engagement.

Each post 16 preferably comprises a U-shaped channel standing verticallyon base 10 and attached thereto by means of an angle bracket 17. The twoposts 16 on the left side of the rack are oriented with their open sidesfacing each other. The two posts 16 on the right side of the cabinet aresimilarly oriented. The flat sides or faces 20 of the channelscomprising posts 16 face forwardly or rearwardly' of the cabinet asshown.

A plurality of tray supports indicated generally at 21 are mounted invertical arrangement on the flat sides 20 of posts 16 at horizontallycorresponding levels so that a plurality of trays can be supported inparallel, vertically spaced horizontal planes by sets of four traysupports 21 on the four cornerposts 16 at each level in the manner ofthe tray shown in FIG. 2 in phantom outline supported at the top levelof the rack. The details of structure and operation of the tray supports2ll will be described in detail later in connection with an explanationof the elevator operation of the rack.

All the trays contained in the rack are simultaneously elevated from onesupport level to the next support level by four movable lifting columns22, one associated with each corner post 16. Base is provided with fourapertures 23 at the bottom ends of posts which permit the liftingcolumns 22 to move up and down and to extend downwardly through andbelow base 10. The lower ends of lifting columns 22 on the left side ofthe rack are rigidly connected beneath base 10 by a horizontal yokemember 24 and, together, comprise a U- shaped lifting structure forlifting the left side of the trays supported in the rack. The tworight-hand movable columns 22 are similarly rigidly connected togetherat their lower ends and beneath base 10 by another yoke member 23 and,together, comprise a U-shaped lifting structure for lifting the rightside of the trays supported in the rack.

Each lifting column 22 preferably comprises a channel or other suitableshape adapted to loosely fit within the channel of a comer post 16 andis free to slide vertically up and down within the channel of itsassociated post while being guided and maintained in vertical alignmentby it. The channel side of each lifting column 22 faces inwardly itsflat face 25 is exposed. Because of the orientation of the cornerpostsas described above, the flat faces 25 of the two left-hand liftingcolumns 22 face each other as shown in FIG. 1. Similarly, the flat faces25 of the two right-hand lifting columns 22 also face each other. Thusthe two left-hand lifting columns 22, rigidly connected by yoke 24, andguided by the two left-hand posts 16, are free only to move togethervertically up and down relative to posts 16 and base 10. The tworight'hand lifting columns 22 are similarly constrained to move togetherwith a vertical up and down motion.

The left and right U-shaped lifting structures are raised and loweredtogether by operation of a foot treadle indicated at 26 in FIGS. 11, 2,and 4. Foot treadle 26 comprises a pair of operating levers 27 pivotallymounted for rocking motion beneath base 10 by means of shaft 28supported by brackets 29. Treadle 26 is connected to the two U-shapedlifting struc tures by means of a cross-shaft 30 passing through slottedapertures 31 of brackets 32 depending from the yokes 24 and the ends ofoperating levers 27. The opposite ends of operating levers 27 extendoutwardly from beneath base 10 and are joined together by a foot bar 33.It will be apparent that downward motion of the foot bar 33 from itsposition as shown in FIG. 4 will cause the opposite end of the levers 27to swing upwardly and carry with them the leftand right-hand U- shapedlifting structures. The mechanical arrangement of treadle 26 and theU-shaped lifting structures as described above insures the simultaneousand equal movement of all four elevating columns throughout the range oftheir up and down travel.

The four lifting columns 22 are provided with means for cooperativelyengaging a tray, basket, or pan at one support level, lifting it to thenext support level and disengaging from the elevated tray to return tothe lower level in preparation for engaging and lifting again. In thepreferred embodiment as shown in FIGS. 2, 5, 6, and 7, such meanscomprise simply a vertically extending heavy, flat plate 34 having twoslots 35 for engagement with a pair of pins 36 extending normally fromthe flat face 25 of each of the elevating columns 22. Enlarged heads onthe ends of the pins 36 hold plates 34 on them. The two slots 35 in eachplate 34 are angularly related and parallel as shown so that the plateis free to move in one direction inwardly and upwardly of the .rackagainst the force of gravity and, in the other direction, downwardly andoutwardly and aided by the force of gravity. Slots 35 fit pins 36loosely so that the weight of plates 34 easily maintains them in therest position shown in FIG. 2, for example. The ease of sliding movementof plates 34 on pins 36 may be promoted by bushing the pins with looserollerlike sleeves.

The inwardly facing, vertically extending sides 37 of each plate 34 areprovided with a series of congruent projections 38, each having ahorizontal upper edge 39 and an inclined lower camming edge 40.Projections 38 extend well into the space between the leftand right-handposts I6 when plates 34 are in their gravity-induced rest position asshown in FIG. 2, for example. When the plates are moved upwardly andoutwardly until pins 36 engage the opposite ends of slots 35 from thatshown in FIG. 2, the projections project little, if at all, beyond theinside faces of posts 16.

Further details of tray supports 21 on posts 16 and of lifting plates 34on lifting columns 22 can best be described in terms of theircooperative operation. FIGS. 5, 6, and 7 each shows a portion of thesame post 116 from a point below the upper surface 15 of conditioningapparatus 12 and extending upwardly some distance therefrom. The post 16is shown in a view from the front, for example, of the rack so thatplate 34 carried on lifting column 22 appears in phantom except forprojections 38 extending into the interior space of the rack. In FIG. 5,a tray is shown positioned at the loading level, the lowest level of therack. The loading level, as explained above, comprises top surface 15 ofconditioning apparatus 12 or any other suitable means for receiving andholding the tray in a horizontal position. The large area flat surfaceas shown herein 'is preferred in order to insure and simplify thesuccessful loading of a tray of food, for example, into the lowermostlevel of the rack. Such an arrangement eliminates the need for'careful,critical alignment of the tray and serves to position and align the trayin its proper position with little, if any, guidance from the operator.It will be noted that the lowermost projection 38 of each plate 34 whenin the rest position as shown in FIG. 5 is such that horizontal upperedge 39 is below and preferably clear of the underside of the tray andextends a substantial distance under the tray for positive engagementwith it.

In FIGS. 5--7, two tray supports 21 are shown on the face 20 of post 16.Each tray support 21 comprises a horizontally extending guide channel 41and a lateral slide 42 guided therein. Each slide 42 is free to movehorizontally back and forth in its guide channel 41 fastened to the face20 of post 16. Slide 42 is retained in the channel by nylon buttons 43pressfitted into suitable holes in the guide channel flanges. Each slide42 is resiliently urged to its extended supporting position as shown inFIG. 5 by springs 44 extending between opposite points on flanges of theassociated guide channel 411 and behind a projecting post 45 carried onslide 42. Each slide 42 is free to move back and forth in its guidechannel 41 in response to applied force. Slide 42 is prevented fromsliding out of its guide channel in one direction by spring 44 and inthe other direction by engagement of the edge of a notch 46 in guidechannel 41 and the end of post 45 projecting from the backside of slide42. The projecting portion 47 of each slide 42 comprises a horizontalupper edge 48 joined by an inclined camming edge 49. All the lateralslides 42 on each of the posts 16 are free to move independently of theother.

FIG. 5 shows a tray supported at the lowest or loading level of therack. FIG. 6 shows the same tray engaged and supported by a projection38 on plate 34 and lifted part of the distance between successivesupport levels. As the tray is lifted, its rolled edge engages the lowerinclined camming edge 49 of the slides 42 of the adjacent tray support21 and earns it outwardly from its normal projecting position. As soonas the bottom of the tray being lifted is raised above the upper end ofinclined camming edge 49 of the slide 42 of a tray support 21, the slideis free and is resiliently returned by spring 44 to its projectingposition with its horizontal upper edge 48 extending beneath theunderside of the tray for full supporting engagement with it. See FIG.7.

All plates 34 and the lifting columns 22 upon which they are mounted aremoved upwardly together to raise the tray upon operation of foot pedal26. Full depression of foot pedal 26 brings the two yokes 24 intoengagement with the underside of base 10. Yokes 24 or the underside ofbase is preferably provided with cushioning and quieting elements suchas rubber stops 50 shown in FIG. 4. The positive parallel relationshipof connecting yokes 24 with the flat underside of base when foot pedal26 is fully depressed insures that all lifting columns 22 are raised thesame amount and, thus, the horizontal alignment of the trays beinglifted is insured. This is an important feature of the apparatusembodying this invention and contributes substantially to itsdesirability and reliability in successfully handling with a minimum ofeffort and attention quantities of trays, baskets, or pans containingfood without spillage or similar accident.

It should be noted that full depression of the foot pedal 26 preferablyprovides an upper extension of lifting columns 22 sufficient to raisethe tray slightly above horizontal upper edges 47 of all adjacent slides42 so that the tray in no way interferes with the resiliently urgedextension of slides 42 into their inwardly projecting tray supportingpositions. Thus, the upper tray-supporting edges 39 of projections 38 onplates 34 of the lifting columns 22 must be able to be raised a distanceslightly greater than the spacing between the upper supporting edges 48of adjacent slides 42. For example, if the tray supports 21 are arrangedto support the bottoms of successive trays a distance of 4 inches apart,it is preferred that the total travel of the tray-lifting columns 22 andtheir plates 34 be 4% 5/8 inches, permitting the projections 38 to startfrom position five-sixteenth inches below the supported tray and lift orelevate it to a position five-sixteenth inches above the next supportlevel.

In FIG. 7, it will be observed that the tray first appearing in FIG. 5at the loading level has been elevated and is now supported at the nexthigher level on slides 42. The elevating means is shown in a partiallylowered position to illustrate how the edge of the tray engages theinclined lower camming edge 40 of projection 38 on plates 34 to urge theplates outwardly and necessarily upwardly, withdrawing the projectionsso they may pass by and below all trays supported in the rack. Oncelifting columns 22 and their associated plates 34 have been lowered to apoint where all projections 38 are out of engagement with supportedtrays, the plates are free to slide by the force of gravity inwardly andoutwardly and as limited by the slots.

Repeated operation of the foot pedal raises all the trays contained inthe rack in successive steps, one level at a time. In the conditionshown in FIG. 7, the rack is able to receive another tray in the bottomloading position. The tray already in the rack may be maintained at thelevel shown in FIG. 7 until another tray is loaded or it may be elevatedby repeated operations of the foot pedal until it reaches the topsupport level on the uppermost supporting slides. A tray in thisposition is shown in FIG. 3 and indicated in dotted outline in FIG. 2.

The uppermost tray support level is the serving position for the foodcontained on the tray theresupported. If a protective cover, such as thetransparent hinged lid shown in FIG. 1, is provided, food can beobtained by raising the cover and removing it from the tray nowpresented at substantially the top surface of the cabinet. When the trayis empty, it is removed through the upper face of the cabinet. Forconvenience, the sideplates are cut away as at 51 in order to providehand room next to the edges of the tray. After the empty tray isremoved, the tray underneath it is raised into the uppermostfood-dispensing position. Thus, as trays are emptied by service of foodfrom the top of the cabinet, filled trays can be presented for serviceby operation of the foot pedal.

As trays of food are prepared for service, they can be introduced to thecabinet at the lowermost position. While in the cabinet and waiting tobe served, the food is maintained at its predetermined desired conditionby appropriate apparatus preferably mounted on the base of the cabinet.It will be observed that the operator loads all newly prepared food intoonly one position. All food to be served appears and is dispensed fromanother position. The operation of the elevating mechanism is such thatthe prepared food first loaded into the rack is the food first presentedfor service. This first in, first out" order of presentation of the foodis highly desirable from a food-handling standpoint and insuresuniformly fresh food for service from an adequate prepared supply sooften desirable in continuous food service establishments. Therelatively small opening areas in the cabinet permits the desiredconditions to be easily maintained within the cabinet. The operation ofthe elevating means is simple and requires but a single motion of theoperator's foot so that his hands are free to safely and effectivelyhandle his duties. It will be understood that racks of variousdimensions holding different numbers of trays, baskets, or pans may beprovided and are comprehended by this invention. The spacing between thesupported elements may be varied, as desired.

From the foregoing, it will be apparent that the invention comprehends arack for supporting a plurality of trays at vertically spaced levels andfor repeatedly lifting simultaneously all supported trays from onesupport level to the next support level by successive actuatingoperations. The rack comprises a base, a fixed pair of multileveltray-supporting structures fixedly mounted laterally opposite each otheron the base. These structures, one on each side of the trays to besupported, are adapted to releasably engage and support at predeterminedvertically spaced levels the laterally opposite sides of trays receivedbetween them. The rack also comprises a pair of movable multileveltray-supporting structures, one of the two being adjacent one of thefixed tray-supporting structures, and the other of the movable pairbeing adjacent the other of said fixed tray structures for releasablyengaging and movably supporting the laterally opposite sides of traysreceived therebetween in fixed vertically spaced relationship at andbetween adjacent levels of support provided by the fixed supportingstructures and for passing supported trays from supported engagement atone level of the fixed supporting structures to the next higher level ofsupported engagement. The two movable supporting structures areinterconnected to each other and to an actuating lever whereby a singlestroke of the operating lever moves both movable tray-supportingstructures together in the direction from one tray support level of thefixed supporting structures to the next higher of such levels.

The movable supporting structures comprising lifting columns 22connected at their lower ends by yokes 24 may be provided with traysupports such as independently movable tray supports 21 described inconnection with the fixedtraysupporting structures rather than the typedescribed comprising plates 34. Indeed, other than tray-supporting meansmay be used on both the fixed and movable tray supporting structures solong as they provide the cooperative operation and relationship of thefixed and movable tray-supporting structures found in the preferredembodiment described above.

The operation of the rack embodying this invention described above maybe carried out with wire baskets, pans, or the like as well as the traysshown and mentioned in connection with the preferred embodiment. Also,the invention is not, of course, limited to a rack having any particularnumber of tray-supporting levels including the number illustrated in thepreferred embodiment. Finally, it will be understood that the foottreadle operation could easily be converted to hand operation byappropriate extensions and handle additions to the structure shown anddescribed.

Those skilled in the art will appreciate that various changes andmodifications can be made in apparatus described herein withoutdeparting from the spirit and scope of the invention.

Iclaim:

1. A rack for supporting a plurality of trays at vertically spacedlevels and for successively lifting simultaneously all supported traysfrom one support level to the next support level by repeated actuatingoperations, said rack comprising a base,

a fixed pair of multilevel tray-supporting structures fixedly mountedlaterally opposite each other on said base for releasably engaging andsupporting at predetermined vertically spaced levels the laterallyopposite sides of trays received therebetween, said fixed pair oftray-supporting structures comprising two laterally spaced, verticalposts fixed to said base, a plurality of independently movable traysupports vertically aligned and mounted on each of said posts atcorresponding predetermined support levels, each of said movable traysupports comprising a fixed horizontal aligned guide, a slide freelyslidable in said guide toward and away from the other of said traysupporting structures and to and between extended tray-engaging andretracted disengaging positions, means resiliently biasing said slidesto their extended engaging and supporting position, said slides having aprojecting inclined camming surface adapted to cam said slide into itsretracted position against the force supplied by said resilient biasingmeans upon application of an upwardly directed force,

a pair of movable multilevel tray-supporting structures, one

of said pair being adjacent one of said fixed tray-supporting structuresand the other of said pair being adjacent the other of said fixed traystructures, for releasably engaging and movably supporting the laterallyopposite sides of trays received therebetween in fixed vertically spacedrelationship at and between adjacent levels of support of said fixedsupporting structures and for passing supported trays from supportedengagement at one level of said fixed supporting structure to the nexthigher level of supported engagement, said movable supporting structuresbeing interconnected to each other and to an actuating lever for movingsaid movable tray-supporting structures together the distance betweenadjacent support levels and in the direction from one tray support levelof said fixed supporting structures to the next higher of such levels.

2. A rack for supporting a plurality of trays at vertically spacedlevels and for successively lifting simultaneously all supported traysfrom one support level to the next support level by repeated actuatingoperations, said rack comprising a base,

a fixed pair of multilevel tray-supporting structures fixedly mountedlaterally opposite each other on said base for releasably engaging andsupporting at predetermined vertically spaced levels the laterallyopposite sides of trays received therebetween,

a pair of movable multilevel tray-supporting structures, one

of said pair being adjacent one of said fixed tray-supporting structuresand the other of said pair being adjacent the other of said fixed traystructures, for releasably engaging and movably supporting the laterallyopposite sides of trays received therebetween in fixed vertically spacedrelationship at and between adjacent levels of support of said fixedsupporting structures and for passing supported trays from supportedengagement at one level of said fixed supporting structure to the nexthigher level of supported engagement, said movable supporting structuresbeing interconnected to each other and to an actuating lever for movingsaid movable tray-supporting structures together the distance betweenadjacent support levels and in the direction from one tray support levelof said fixed supporting structures to the next higher of such levels,said movable tray-supporting structures comprising a generally U-shapedlifting assembly having a pair of laterally spaced-apart longitudinallyextending lifting columns passing through and movable up and down withrespect to said base, a horizontal yoke element connecting the lowerends of said lifting columns together beneath said base for holding saidcolumns in a fixed lateral relationship and for engagement with stopshaving a fixed relationship with the underside of said base uponoperation of said actuating lever to insure the equal elevation of saidconnected lifting columns, and tray-supporting and engaging meansmounted on each of said lifting columns and each movable betweenextended tray-engaging and supporting and retracted disengagingpositions, biasing means tending to urge said tray-engaging means towardthe extended position, said tray-engaging and supporting means adaptedto be cammed into its retracted position against the force of saidbiasing means upon application of an upwardly directed force.

3. The rack according to claim 2 in which said tray-engaging andsupporting means are spaced on said lifting column to support traysengaged by them at vertical intervals corresponding to the intervalsbetween the tray support levels provided by said multileveltray-supporting structures and in which said lifting columns are movableup and down a distance at least slightly greater than the intervalsbetween said tray support levels.

4. The rack according to claim 2 in which said movable tray-engagingsupporting means comprises a plate slidably mounted on and associatedwith each lifting column by at least two inclined slots in said plateand associated pins extending from its associated column and received intheir associated slots to permit said plates lifting assembly of one ofsaid movable tray-supporting structures to move in one directionupwardly and away from the other of said movable tray-supportingstructures to a retracted position and in the opposite direction t anextended position, each of said plates having a plurality of projectionsspaced up and down said plates at intervals corresponding to the spacingof said tray support levels of said fixed tray-supporting structures andextending from one toward the other of said movable tray-supportingstructures, each of said projections having an inclined cam adapted tocam said projection and the plate it comprises into its retractedposition upon application of an upwardly directed force.

5. The rack according to claim 1 in which each of said movabletray-supporting structures comprises a generally U-shaped liftingassembly having a pair of laterally spaced-apart longitudinallyextending lifting columns passing through and movable up and down withrespect to said base,

a horizontal yoke element connecting the lower ends of said liftingcolumns together beneath said base for holding said columns in a fixedlateral relationship and for engagement with stops having a fixedrelationship with the underside of said base upon operation of saidactuating lever to insure the equal elevation of said connected liftingcolumns,

and tray engaging and supporting means mounted on each of said liftingcolumns and each movable between extended tray engaging and supportingand retracted disengaging positions, biasing means tending to urge saidtray engaging means toward the extended position, said trayengaging andsupporting means adapted to be cammed into its retracted positionagainst the force of said basing means upon application of an upwardlydirected force.

6. The rack according to claim 5 in which said vertical posts and saidlifting columns comprise longitudinally extending channel sections, eachhaving an open-channeled face and a flat face, and in which each posthas lifting column associated with it, the open-channeled faces ofassociated posts and lifting columns facing toward each other and fittedtogether for guiding engagement of the movable lifting columns by thefixed posts during relative longitudinal movement between them, and withthe flat faces of associated posts and lifting columns facing away fromeach other, said movable tray supports being mounted on the flat facesof said posts and said tray engaging and supporting means being mountedon the flat faces of said lifting columns.

7. A rack for supporting a plurality of trays at vertically spacedlevels and for successively lifting simultaneously all supported traysfrom one support level to the next support level by repeated actuatingoperations, said rack comprising a base,

a fixed pair of multilevel tray-supporting structures fixedly mountedlaterally opposite each other on said base for releasably engaging andsupporting at predetermined vertically spaced levels the laterallyopposite sides of trays received therebetween, said fixed pair oftray-supporting structures comprising two laterally vertical posts ofchannel cross section having an open-channeled face and a flat face,said posts being fixed to said base, and a plurality of independentlymovable tray supports vertically aligned and mounted on the flat face ofeach of said posts at corresponding predetermined support levels, and

a pair of movable multilevel tray-supporting structures, one

tuating lever for moving said movable tray-supporting structurestogether the distance between adjacent support levels and in thedirection from one tray support level of said fixed supportingstructures to the next higher of such levels, each of said movabletray-supporting structures comprising a lifting column associated witheach of said posts and passing through and movable up and down withrespect to said base, said lifting columns being of channel crosssection having an open-channeled face and a flat face, and a pluralityof tray engaging and supporting means mounted on the flat face of eachof said lifting columns at vertically spaced intervals corresponding tosaid predetermined support levels, the open-channeled faces ofassociated posts and lifting columns facing toward each other and fittedtogether for guiding engagement of the movable lifting columns by thefixed posts during relative longitudinal movement between them.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 I O15Dated July 6 I 1971 Inventor(s) Blaise d 'Anka It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Title Page, change the inventor 's name from "Blasie d Anka" to Blaised'Anka-.

Abstract, line 5, change "form" to from--.

Column 3, line 26, after "inwardly" insert --and--.

Column 5, lines 22 and 23, change "and their plates 34 be 4% 5/8 inches"to read -and their plates 34 be 4-5/8 inches-;

line 23, after "from" insert --a--.

Column 7, line 6, change "horizontal" to -horizontally-.

Column 8. line 22, change "direction t an extended position" to readdirection to an extended position--.

Signed and sealed this 25th day of January I972.

(SEAL) Attost:

EITWARD M. FLETCHER, JR ROBERT GOTTSCHALK i -lctestlng Officer-Commissioner of Patents FORM PC3-1050 USCOMM-DC 60376-P69 Q U 5GOVERNMENT PRINTlNG QFFICE' 19.9 D-356'33l

1. A rack for supporting a plurality of trays at vertically spacedlevels and for successively lifting simultaneously all supported traysfrom one support level to the next support level by repeated actuatingoperations, said rack comprising a base, a fixed pair of multileveltray-supporting structures fixedly mounted laterally opposite each otheron said base for releasably engaging and supporting at predeterminedvertically spaced levels the laterally opposite sides of trays receivedtherebetween, said fixed pair of tray-supporting structures comprisingtwo laterally spaced, vertical posts fixed to said base, a plurality ofindependently movable tray supports vertically aligned and mounted oneach of said posts at corresponding predetermined support levels, eachof said movable tray supports comprising a fixed horizontal alignedguide, a slide freely slidable in said guide toward and away from theother of said tray supporting structures and to and between extendedtray-engaging and retracted disengaging positions, means resilientlybiasing said slides to their extended engaging and supporting position,said slides having a projecting inclined camming surface adapted to camsaid slide into its retracted position against the force supplied bysaid resilient biasing means upon application of an upwardly directedforce, a pair of movable multilevel tray-supporting structures, one ofsaid pair being adjacent one of said fixed tray-supporting structuresand the other of said pair being adjacent the other of said fixed traystructures, for releasably engaging and movably supporting the laterallyopposite sides of trays received therebetween in fixed vertically spacedrelationship at and between adjacent levels of support of said fixedsupporting structures and for passing supported trays from supportedengagement at one level of said fixed supporting structure to the nexthigher level of supported engagement, said movable supporting structuresbeing interconnected to each other and to an actuating lever for movingsaid movable traysupporting structuRes together the distance betweenadjacent support levels and in the direction from one tray support levelof said fixed supporting structures to the next higher of such levels.2. A rack for supporting a plurality of trays at vertically spacedlevels and for successively lifting simultaneously all supported traysfrom one support level to the next support level by repeated actuatingoperations, said rack comprising a base, a fixed pair of multileveltray-supporting structures fixedly mounted laterally opposite each otheron said base for releasably engaging and supporting at predeterminedvertically spaced levels the laterally opposite sides of trays receivedtherebetween, a pair of movable multilevel tray-supporting structures,one of said pair being adjacent one of said fixed tray-supportingstructures and the other of said pair being adjacent the other of saidfixed tray structures, for releasably engaging and movably supportingthe laterally opposite sides of trays received therebetween in fixedvertically spaced relationship at and between adjacent levels of supportof said fixed supporting structures and for passing supported trays fromsupported engagement at one level of said fixed supporting structure tothe next higher level of supported engagement, said movable supportingstructures being interconnected to each other and to an actuating leverfor moving said movable tray-supporting structures together the distancebetween adjacent support levels and in the direction from one traysupport level of said fixed supporting structures to the next higher ofsuch levels, said movable tray-supporting structures comprising agenerally U-shaped lifting assembly having a pair of laterallyspaced-apart longitudinally extending lifting columns passing throughand movable up and down with respect to said base, a horizontal yokeelement connecting the lower ends of said lifting columns togetherbeneath said base for holding said columns in a fixed lateralrelationship and for engagement with stops having a fixed relationshipwith the underside of said base upon operation of said actuating leverto insure the equal elevation of said connected lifting columns, andtray-supporting and engaging means mounted on each of said liftingcolumns and each movable between extended tray-engaging and supportingand retracted disengaging positions, biasing means tending to urge saidtray-engaging means toward the extended position, said tray-engaging andsupporting means adapted to be cammed into its retracted positionagainst the force of said biasing means upon application of an upwardlydirected force.
 3. The rack according to claim 2 in which saidtray-engaging and supporting means are spaced on said lifting column tosupport trays engaged by them at vertical intervals corresponding to theintervals between the tray support levels provided by said multileveltray-supporting structures and in which said lifting columns are movableup and down a distance at least slightly greater than the intervalsbetween said tray support levels.
 4. The rack according to claim 2 inwhich said movable tray-engaging supporting means comprises a plateslidably mounted on and associated with each lifting column by at leasttwo inclined slots in said plate and associated pins extending from itsassociated column and received in their associated slots to permit saidplates lifting assembly of one of said movable tray-supportingstructures to move in one direction upwardly and away from the other ofsaid movable tray-supporting structures to a retracted position and inthe opposite direction t an extended position, each of said plateshaving a plurality of projections spaced up and down said plates atintervals corresponding to the spacing of said tray support levels ofsaid fixed tray-supporting structures and extending from one toward theother of said movable tray-supporting structures, each of saidprojections having an inclined cam adapted to cam said projection andthe plate it comprises into its retracted position upon application ofan upwardly directed force.
 5. The rack according to claim 1 in whicheach of said movable tray-supporting structures comprises a generallyU-shaped lifting assembly having a pair of laterally spaced-apartlongitudinally extending lifting columns passing through and movable upand down with respect to said base, a horizontal yoke element connectingthe lower ends of said lifting columns together beneath said base forholding said columns in a fixed lateral relationship and for engagementwith stops having a fixed relationship with the underside of said baseupon operation of said actuating lever to insure the equal elevation ofsaid connected lifting columns, and tray engaging and supporting meansmounted on each of said lifting columns and each movable betweenextended tray engaging and supporting and retracted disengagingpositions, biasing means tending to urge said tray engaging means towardthe extended position, said tray-engaging and supporting means adaptedto be cammed into its retracted position against the force of saidbasing means upon application of an upwardly directed force.
 6. The rackaccording to claim 5 in which said vertical posts and said liftingcolumns comprise longitudinally extending channel sections, each havingan open-channeled face and a flat face, and in which each post haslifting column associated with it, the open-channeled faces ofassociated posts and lifting columns facing toward each other and fittedtogether for guiding engagement of the movable lifting columns by thefixed posts during relative longitudinal movement between them, and withthe flat faces of associated posts and lifting columns facing away fromeach other, said movable tray supports being mounted on the flat facesof said posts and said tray engaging and supporting means being mountedon the flat faces of said lifting columns.
 7. A rack for supporting aplurality of trays at vertically spaced levels and for successivelylifting simultaneously all supported trays from one support level to thenext support level by repeated actuating operations, said rackcomprising a base, a fixed pair of multilevel tray-supporting structuresfixedly mounted laterally opposite each other on said base forreleasably engaging and supporting at predetermined vertically spacedlevels the laterally opposite sides of trays received therebetween, saidfixed pair of tray-supporting structures comprising two laterallyvertical posts of channel cross section having an open-channeled faceand a flat face, said posts being fixed to said base, and a plurality ofindependently movable tray supports vertically aligned and mounted onthe flat face of each of said posts at corresponding predeterminedsupport levels, and a pair of movable multilevel tray-supportingstructures, one of said pair being adjacent one of said fixedtray-supporting structures and the other of said pair being adjacent theother of said fixed tray structures, for releasably engaging and movablysupporting the laterally opposite sides of trays received therebetweenin fixed vertically spaced relationship and and between adjacent levelsof support of said fixed supporting structures and for passing supportedtrays from supported engagement at one level of said fixed supportingstructure to the next higher level of supported engagement, said movablesupporting structures being interconnected to each other and to anactuating lever for moving said movable tray-supporting structurestogether the distance between adjacent support levels and in thedirection from one tray support level of said fixed supportingstructures to the next higher of such levels, each of said movabletray-supporting structures comprising a lifting column associated witheach of said posts and passing through and movable up and down withrespect to said base, said lifting columns being of channel crosssection having an open-channeled face and a flaT face, and a pluralityof tray engaging and supporting means mounted on the flat face of eachof said lifting columns at vertically spaced intervals corresponding tosaid predetermined support levels, the open-channeled faces ofassociated posts and lifting columns facing toward each other and fittedtogether for guiding engagement of the movable lifting columns by thefixed posts during relative longitudinal movement between them.